Level indicator sending unit



g- 16, 1956 R. B. COLEMAN ETAL 3,266,312

LEVEL INDICATOR SENDING UNIT Filed Feb. 17, 1964 INVENTORS United StatesPatent 3,266,312 LEVEL INDICATOR SENDING UNIT Richard B. Coleman andNeal E. Neese, Lansing, Mich., assignors to General Motors Corporation,Detroit, Mich., a corporation of Delaware Filed Feb. 17, 1964, Ser. No.345,413 8 Claims. (Cl. 73-313) This invention relates to liquid levelindicators and more particularly to sending units suitable for use inliquid fuel tanks and by means of which signals may be imparted toliquid level indicators such as gages.

An object of the present invention is to provide a combined suction lineand signal sending unit which is low in cost, convenient to install in atank and such as to present a base readily receiving a filter element asa part of the unitand adapted to clarify fluid to be discharged from thetank.

, A feature of the invention is a combined suction line and sending unithaving a cover or support for multiple rods and a conduit, the rodsbeing utilized in conveying a signal current and cooperating with theconduit to guide a float. Another feature is a sending unit employing aresistance and having a conduit for guiding a float and a base forming aconvenient attachment for filter means through which fluid may pass onits way to the conduit.

These and other important features of the invention will now bedescribed in detail in the specification and then pointed out moreparticularly in the appended claims.

In the drawings:

FIGURE 1 is a side view of an automotive gasoline tank, a portion ofwhich is broken away showing the installation of a sending unitrepresenting one embodiment of the present invention;

FIGURE 2 is a view, drawn to a larger scale, of the sending unit shownin FIGURE 1 with portions of the sending unit broken away and a portionof the top wall of the tank shown in section;

FIGURE 3 is a view drawn partly in section as viewed in the direction ofthe arrows 33 in FIGURE 2;

FIGURE 4 is a sectional view looking in the direction of the arrows 44in FIGURE 2; and

FIGURE 5 is a sectional view looking in the direction of the arrows 55in FIGURE 2.

An automotive type fuel tank is shown at having a top wall 12 with adischarge opening therein shown at 14 as being reinforced by astiffening ring 16. A support 18 is formed as a cover for the opening 14and is so made as to be attachable to the tank by means of screws 20with a sealing gasket 22 interposed. The cover 18 is preferablyinjection molded of plastic material in such a way as to include a rightangle portion 24 defining a right angle suction passage. One side of thecover 18 is formed to constitute a tube-like projection or nipple 26suitable for the attachment of a suction line such as indicated at 28.Depending from the main body of the cover 18 is a tube portion 30. Aconduit 32 is pressed on the tube portion 30 so that the passage fromthe portion 24 is thereby extended downwardly a substantial distance andbelow a metal base plate 34. This base plate surrounds the conduit 32and is joined to the cover 18 and in spaced relation with the latter bymeans of three rods 36, 38 and 40.

The rod 36 is retained at one end within the cover 18 in such a way asto constitute a terminal insulated by the cover from the material of thetank 10. The other end of the rod 36 is reduced in diameter and heldwithin an insulator bushing 42 pressed into the metal base plate 34. Therod 38 is also held by the cover 18 and insulated from the tank toconstitute a terminal as is the case with the rod 36, but in this casethe rod 38 is fixed in conductive relation with the base plate 34. Therod 40 is preferably made of glass filled nylon or plastic material andhas its "ice upper end pressed into and concealed within the cover 18and its lower end in a driving fit with the cover 34. The rod 40 alsocarries a resistance 44 which is in the form of a coil of spacedconvolutions of resistance wire. One end is held in conductive relationwith the base plate 34 through a nickel silver ferrule 47. A secondferrule 48 is used at the other end of the rod 40 to anchor that end ofthe wire 44.

Integral with the conduit 32 is a disk 46 having a peripheral flange 46and made integral with the conduit and such as to provide a surface forclosure and support of a Saran mesh bag-like filter element 50 which ispinched or closed at its base 52. Preferably the proportions are suchthat the element 50 just contacts the bottom of the tank 10.

Slidable on the conduit 32 is a plastic float 54 which bears peripheralnotches such as at 56 slidingly to receive the rods 36, 38 and 40. Thefloat 54 carries contact means 60 in the form of a spring ribbon in sucha way that one end of the contact means 60 slidably engages the rod 36and the other end engages the resistance 44.

It will be noted that the structure permits the choice of plasticmaterial for the making of the conduit 32 and the cover 18. This isconducive to low cost and yet provides a very satisfactory structure forfirmly guiding the float 54 and most satisfactorily support the filterelement 50.

The rod 36 has its upper end spaced to form a terminal for connection toa gage 72 which is connected to a source of voltage such as battery 70.The base plate 34 is in conductive relation with the rod 38 and theupper end of the latter presents an exterior terminal for connection toground 74. A suitable fuel gage is disclosed in United States Patent No.2,883,623, granted April 21, 1959, in the names of H. R. Hastings and C.A. Haut. Numerous equivalent instruments would serve to give anindication of float level in accordance with a correct signal impartedby the tank sending unit herein disclosed.

In the operation of the unit the variation in the supply of liquid fuelin the tank 10 will cause the rising and falling of the float 54 andthis will cause a variation of the current passing through theresistance 44 and influence the reading of the gage 72. It will beunderstood that the circuit will proceed from the gage 72, down the rod36 to the ribbon or contact means 60, along the latter to the resistance44 and then to the base plate 34 and to the second metal rod 38 and thento ground 74. In the claims as set forth below, the rod 38 is referredto as the second rod and the rod 36 as the one other rod.

When suction is applied by way of the inlet conduit 28 to the suctionpassage defined by the cover 18 and the conduit 32, gasoline will flowthrough the filter 50 and be suitably clarified simultaneously with thesending of the signal as to fluid level by the same unitary structure.

We claim:

1. A liquid level sending unit comprising a first cover at one endadapted to be fixed to the top wall of a tank, a second cover spacedfrom said first cover, filtering means at the other end of said unit andsupported by said second cover for submergence in said tank, a conduiton said first cover and defining a suction passage leading through bothcovers to said filtering means, multiple rods fixed to said covers andextending along a length portion of said conduit, a resistance elementextending along one of said rods with one end of said elementelectrically connected to a second of said rods, a float movable alongsaid length portion of said conduit and carrying contact means slidableon said resistance and one other of said rod-s, and terminals on saidsecond and one other rods.

2. A liquid level sending unit comprising a cover adapted to be fixed tothe wall of a tank and a filtering means for submergence in said tank,said cover and filtering means being connected by a central conduit andmultiple rods spaced around the said conduit, the conduit defining asuction passage leading through the said cover, resistance means on oneof said rods and having one end in electrically conductive relation witha second of said rods, a float slidable on said conduit, contact meanson said float slidable on said resistance means and one other of saidrods, and terminals on said second and one other rods.

3. A liquid level sending unit comprising a cover attachable to a tankand including a filtering unit supported in spaced relation on saidcover by means of three rods and a conduit, said conduit and coverdefining a suction passage leading from the interior of said filteringunit and through the cover, a resistance on one of said rods, saidfiltering unit including a metal plate in electrical conducting relationwith one end of said resistance and a second of said rods, a floatmovable along said conduit and carrying contact means slidable on saidresistance and one other of said rods, and terminals on said second andone other rods.

4. A liquid level sending unit comprising a plastic cover attachable toa tank and including a filtering unit fixed in spaced relation to saidcover by means of multiple metal rods and a plastic conduit, saidconduit and cover cooperating to define a suction passage leading fromone side of said cover to the interior of said filtering unit on theother side of said cover, a resistance on one of said rods, one end ofsaid resistance being connected to a second of said rods, a floatmovable along said conduit and rods, contact means carried by said floatand slidable on said resistance and one other of said rods and terminalson said second and one other rods.

5. A liquid level sending unit comprising a cover attachable to a tankwall and including a base plate fixed in spaced relation to said coverby multiple rods and a central conduit, said rods and base platecooperating in carrying a resistance whereby current may be conductedthrough the unit, a float movable on said conduit between said cover andbase plate and carrying contact means slidable on said resistance tovary said current, and one end of said central conduit being open andterminatnig near said base plate.

6. A liquid level sending unit attachable to a tank wall and including asupport and a metal base plate, multiple rods and a conduit connectingsaid support and base plate in spaced relation, a float slidable on saidconduit and having grooves each in registry with one of said rods forguidance, a resistance on one of said rods and having one end connectedto said base plate, a second of said rods having a terminal at one endand its other end in conductive relation with said base plate, contactmeans carried on said float and slidable on said resistance and oneother of said rods, and a terminal on said one other rod.

7. A liquid level sending unit as set forth in claim 6 in which saidsupport and conduit are made of plastic and which cooperate in defininga suction passage.

8. A liquid level sending unit as set forth in claim 6 including abag-like filter element and in which said base plate and one end of saidconduit form a closure for said bag-like filter element.

References Cited by the Examiner UNITED STATES PATENTS Re. 25,208 7/1962Perkins 73-313 1,281,658 10/1918 Remy et al. 2,125,219 7/1938 Campbell73-313 X 3,023,905 3/1962 McDougal et al 210-172 LOUIS R. PRINCE,Primary Examiner.

DAVID SCHONBERG, Examiner.

DONN MCGIEHAN, Assistant Examiner.

1. A LIQUID LEVEL SENDING UNIT COMPRISING A FIRST COVER AT ONE ENDADAPTED TO BE FIXED TO THE TOP WALL OF A TANK, A SECOND COVER SPACEDFROM SAID FIRST COVER, FILTERING MEANS AT THE OTHER END OF SAID UNIT ANDSUPPORTED BY SAID SECOND COVER FOR SUBMERGENCE IN SAID TANK, A CONDUITON SAID FIRST COVER AND DEFINING A SUCTION PASSAGE LEADING THROUGH BOTHCOVERS TO SAID FILTERING MEANS, MULTIPLE RODS FIXED TO SAID COVERS ANDEXTENDING ALONG A LENGTH PORTION OF SAID CONDUIT, A RESISTANCE ELEMENTEXTENDING ALONG ONE OF SAID RODS WITH ONE END OF SAID ELEMENTELECTRICALLY CONNECTED TO A SECOND OF SAID RODS, A FLOAT MOVABLE ALONGSAID LENGTH PORTION OF SAID CONDUIT AND CARRYING CONTACT MEANS SLIDABLEON SAID RESISTANCE AND ONE OTHER OF SAID RODS, AND TERMINALS ON SAIDSECOND AND ONE OTHER RODS.